ST- service bulletin [RE-wrenches]

[Steve Bell]

Hi Marco,

I believe that the 8% figure from Trace is probably realistic. It was I who
first posted a message about the ST problems and asked for further
input/experience from other ST installations. Since then I have had numerous
conversations with Dean, Tobin, Geoff, Gort and Ezra at Trace. They have all
been quite honest and open with trying to help with the few problem
installations that  we have. Only 4 ST-systems out of the many we have
supplied to dealers, have reported problems. Not all of the problems were
caused by the ST, one installation had three different sub-arrays, each with
a different brand/model of PV module, all feeding into a single ST inverter.
Imagine the ST's confusion trying to track the MPPT of three different IV
curves.

It appears that the first STs did have some problems with their displays
acting up once it was in the field. Trace came up with several fixes for
those problem sites. I believe they also incorporated these fixes/upgrades
into all new units going out the door. The aggressive MPPT algorithm
situation was clearly explained in the service bulletin. It is my
understanding that the somewhat less aggressive firmware will be the
"standard isuue" for new units.

This has been my experience working with Trace relative to problem ST
installations.


Sincerely,
Steve Bell
SunWize Technologies
sebpv at stelle.net




----- Original Message -----
From: <mmangelsdorf at hei.com>
To: <RE-wrenches at topica.com>
Cc: <sburns at hei.com>
Sent: Tuesday, March 20, 2001 02:15 PM
Subject: RE: Unisolar Roofing [RE-wrenches]



> On another note, you did hear that Trace Tech. now has high voltage,
> UL-listed combiner boxes?  Regarding the SunTie tales of woe, what's your
> impression of their recent technical service bulletin?  And the part that
> talked about a failure rate of 8 percent of the STs in the field?  Based
on
> the comments from the wrenches list, one would think that the incidence of
> MPPT problems and frequent cut-outs was higher than a little ole 8 out of
> 100.
>
> aloha,
> marco


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